Currently, in a wireless personal communications system (WPAN), application of a 60 gigahertz (GHz) frequency band has aroused people's interest, because people need a bandwidth higher than 7 GHz. Requirements for such a high bandwidth and a millimeter wave bring about many challenges for design of a microwave terminal application. Usually, a 60 GHz wireless front-end product is implemented based on expensive gallium arsenide microwave integrated circuits. Some wireless front-end products are implemented based on silicon-germanium integrated circuits to reduce costs. In such front-end products, an antenna and a chip are usually disposed together, or an antenna is included in a packaging body (system in chip or system on chip) using multiple modules. An antenna plays a very important role in the application of the 60 GHz bandwidth. In a latest technology, an antenna may be designed on a conventional dielectric layer substrate, and an antenna and a chip are simultaneously packaged into a packaging body using a multichip module (MCM) packaging technology. Therefore, costs and a size can be reduced, and a feature and specifications of a communications chip can be implemented, thereby enhancing competitiveness of the product.
In the other approaches, manners for implementing a 60 GHz antenna device in a packaging body mainly include: 1) a multi-layer dielectric layer substrate is used, where an antenna array is disposed on a first layer, a feeder is disposed on a second layer, and a ground plane is disposed on the second layer or a third layer to implement integration of a passive antenna device; and 2) an antenna is designed on an integrated circuit, a substrate is disposed below the integrated circuit, and a passive device is directly bonded to a chip using a packaging technology.
In other approaches, a 60 GHz antenna device is implemented on a substrate in a packaging body. The antenna is implemented in a feeder-to-slot manner. To match a slot antenna, the antenna is implemented by means of a slot bended for 90°. An input line of a slot feeder and an input line of the feeder are on a same straight line. With this design, an area is reduced and a bandwidth can be increased. The antenna structure is designed in a metal carrier with a forked slot, so that the antenna has a relatively high strength, and can be easily integrated with a metallic reflector. The antenna is generally fabricated based on a substrate with multiple layers of low temperature co-fired ceramic (LTCC).
However, when the antenna with the foregoing structure is used, in many processes for implementing antenna packaging, if the antenna uses slot feeding, an antenna gain is greatly affected by a fabrication process, and an antenna frequency bandwidth is not easily controlled. This integration manner cannot be implemented in some mass fabrication scenarios.
In other approaches, multiple support layers and a patch antenna array are disposed on a top layer of a substrate, a feeder between a first dielectric layer and a second dielectric layer is used for antenna feed-in, and a ground plane is disposed between the second dielectric layer and a third dielectric layer.
In other approaches, feed-in is performed on the second layer, if a return loss is −10 decibels (dB), a bandwidth is approximately 4.6 GHz; and a return loss of a 65 GHz antenna is only 7 dB. Because an antenna gain is relatively low, 16 patch antennas are used to increase the gain. Consequently, an area increases, and an antenna feature is not good.